High-Voltage semiconductor devices such as High-Voltage Metal-Oxide-Semiconductor (HVMOS) devices are commonly used in various electronic devices, such as power management systems, AC/DC converters, input/output (I/O) circuits, etc. The HVMOS devices are designed to sustain high voltages, and thus dimensions and structures of HVMOS devices are different from other semiconductor devices such as logic devices formed on the same semiconductor substrate. Due to their different structures and dimensions, integration of HVMOS devices and other semiconductor devices in fabrication faces challenges.